Smartin 1,613 Posted February 3 Share Posted February 3 I wish I was closer. It's always good to walk away for a day if you find yourself frustrated. Link to post Share on other sites
NC-car-guy 3,129 Posted February 3 Author Share Posted February 3 Had to pull forward into the garage. With no verse and a muddy yard its going to be a while before I can take it back out Link to post Share on other sites
old-tank 3,703 Posted February 3 Share Posted February 3 After checking again for vacuum leaks, check continuity of the wires and change the plugs. I have had long dormant engines with new appearing plugs fail to run well. And if some misguided person installed platinum or other exotic plugs, throw them away. Autolite 85 or 75 will serve you well. Link to post Share on other sites
NC-car-guy 3,129 Posted February 3 Author Share Posted February 3 9 minutes ago, old-tank said: After checking again for vacuum leaks, check continuity of the wires and change the plugs. I have had long dormant engines with new appearing plugs fail to run well. And if some misguided person installed platinum or other exotic plugs, throw them away. Autolite 85 or 75 will serve you well. Shes got all new auto lite 85s in it but I suppose I can scrap two and replace. But I have tried switching the plugs around and that didnt seem to change anything. The wires are whatever was on it when I got it. Again I tried switching them around and it had no effect but suppose I can replace them too. I will try for more vacuum leaks, maybe just go ahead and reseat the intake. Link to post Share on other sites
avgwarhawk 4,012 Posted February 3 Share Posted February 3 1 minute ago, NC-car-guy said: Shes got all new auto lite 85s in it but I suppose I can scrap two and replace. But I have tried switching the plugs around and that didnt seem to change anything. The wires are whatever was on it when I got it. Again I tried switching them around and it had no effect but suppose I can replace them too. I will try for more vacuum leaks, maybe just go ahead and reseat the intake. If you have have verified all ignition components are good then look again for a vacuum leak. I would replace the spark plug wires. These are unknown. 1 Link to post Share on other sites
NC-car-guy 3,129 Posted February 3 Author Share Posted February 3 Also it has a pertronix in it from previous, previous owner... Could that affect only 2 cylinders? Link to post Share on other sites
avgwarhawk 4,012 Posted February 3 Share Posted February 3 3 minutes ago, NC-car-guy said: Also it has a pertronix in it from previous, previous owner... Could that affect only 2 cylinders? One way to find out....put in the points! Then leave them in there! 1 1 Link to post Share on other sites
JohnD1956 5,894 Posted February 3 Share Posted February 3 isolate the spark plug wires to eliminate crossfire. New or old, insulate them till you know they are not part of the problem. Link to post Share on other sites
MrEarl 8,746 Posted February 3 Share Posted February 3 19 hours ago, NC-car-guy said: I don't see how a coil would affect only two cylinders and even on those two I can pull the wire almost an inch away and get the spark to jump 19 hours ago, JohnD1956 said: Do you have a spare coil to test it with? 23 minutes ago, NC-car-guy said: Also it has a pertronix in it from previous, previous owner... Could that affect only 2 cylinders? First, what JD said with a sort of qualifier. Try a KNOWN GOOD coil. I once went through most everything you've done on an engine that would run fine at idle and until it got at operating temperature but would skip and die when ran for awhile.I finally put on a new coil, still to no avail. Ran the problem by an old mechanic friend and he said it's got to be the coil. Swapped it with one from another good runner and problem solved. Couple that with the fact it has the Petronix (news to me) and the original coil and I'm thinking you've found the gremlin. Link to post Share on other sites
dmfconsult 578 Posted February 3 Share Posted February 3 2 hours ago, NC-car-guy said: Also it has a pertronix in it from previous, previous owner... Could that affect only 2 cylinders? I think you just nailed the problem. I have heard of Petronix units failing and having this affect. Link to post Share on other sites
NC-car-guy 3,129 Posted February 3 Author Share Posted February 3 16 minutes ago, dmfconsult said: I think you just nailed the problem. I have heard of Petronix units failing and having this affect. Oh really? Well I'll swap some points in tonight. I have 6 distributors hanging up, one's gotta have a serviceable set of points to it...lol 1 Link to post Share on other sites
avgwarhawk 4,012 Posted February 3 Share Posted February 3 7 minutes ago, NC-car-guy said: Oh really? Well I'll swap some points in tonight. I have 6 distributors hanging up, one's gotta have a serviceable set of points to it...lol I would have dumped the Pertronix from day one. Ain't no question.... Link to post Share on other sites
lancemb 1,572 Posted February 3 Share Posted February 3 I am very curious to see if this fixes it. I can't imagine how it would have this effect. I love my Pertronix but keep a set of points in the glovebox just in case! Link to post Share on other sites
avgwarhawk 4,012 Posted February 3 Share Posted February 3 5 minutes ago, lancemb said: I am very curious to see if this fixes it. I can't imagine how it would have this effect. I love my Pertronix but keep a set of points in the glovebox just in case! You keep the old engineered points in the glove box just in case the newly upgraded Pertronix fails? Why not just another set of points? Just curious. Link to post Share on other sites
old-tank 3,703 Posted February 3 Share Posted February 3 Pertronix? Check or replace the rotor too. If the Pertronix was wired to bypass the ballast resistor the central carbon core in the rotor will arc and may even catch fire (happened to me in at a Little Rock hot truck stop)...especially if it is the original rotor! 1 Link to post Share on other sites
lancemb 1,572 Posted February 3 Share Posted February 3 2 hours ago, avgwarhawk said: You keep the old engineered points in the glove box just in case the newly upgraded Pertronix fails? Why not just another set of points? Just curious. Pertronix won't fail due to moisture, corrosion, etc. after sitting a few winter months as points used to do on me. They won't experience slowly degrading performance like points do. They will, however, eventually fail; nothing lasts forever. When they do, it's often sudden. I've been running Pertronix for about 10 years and 5k miles and have had no issues. But, if one day it suddenly fails I have a backup until I can order another. 1 Link to post Share on other sites
Ben Bruce aka First Born 3,454 Posted February 4 Share Posted February 4 1 hour ago, lancemb said: Pertronix won't fail due to moisture, corrosion, etc. after sitting a few winter months as points used to do on me. They won't experience slowly degrading performance like points do. They will, however, eventually fail; nothing lasts forever. When they do, it's often sudden. I've been running Pertronix for about 10 years and 5k miles and have had no issues. But, if one day it suddenly fails I have a backup until I can order another. I am with you. Only I went the next step to HEI. Ben Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 Well...buttercup's groove is gone. Pulling the heads this week. I replaced the entire ignition system, going back to points. Plugged every vacuum port. Retourqed the intake and checked for leaks with propane...all brought no joy. I took the valve covers of and watched the rockers for signs of an issue. Nothing I decided to redo the compression test.... Ah cr@p! I was sure I'd checked every cylinder but I guess I missed one in my initial moment while stressing out. #8 cylinder has no compression. Pulled the rocker assembly and there it was. One valve sitting lower than the rest. It still travels up and down, just not all the way up. I sure hope is just the valve and I've not busted a piston too. 😭😭😭😭😭😭 Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 Barring any damage to the head or piston, can I just lap in a new valve? Should I replace head gaskets again? Should I replace the head bolts? Link to post Share on other sites
JohnD1956 5,894 Posted February 4 Share Posted February 4 Before tearing it down have you considered pulling the valve up and charging the cylinder with pressurized air? Might just be a broken spring on that valve. If the seats were addressed when you had the heads off previously I don't think a seat could be ruined with what little use it has had since then.if the air holds that valve in position, changing that spring might be enough to get her back in the groove. 1 Link to post Share on other sites
avgwarhawk 4,012 Posted February 4 Share Posted February 4 (edited) Pull just the head with the issue. Once out a better determination of repair can be made. Yes, new head gasket and intake gaskets. Reuse the head bolts. Edited February 4 by avgwarhawk (see edit history) Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 20 minutes ago, JohnD1956 said: Before tearing it down have you considered pulling the valve up and charging the cylinder with pressurized air? Might just be a broken spring on that valve. If the seats were addressed when you had the heads off previously I don't think a seat could be ruined with what little use it has had since then.if the air holds that valve in position, changing that spring might be enough to get her back in the groove. Seats were not previously addressed. At 13k miles that thought did not cross my mind. Unfortunately I cant pull up on the valve, hence stuck. Matt Martin told me that as little as 1 liter of bad fuel in an entire tank can gum up the valve stem and cause it to bend like this one. Link to post Share on other sites
Smartin 1,613 Posted February 4 Share Posted February 4 When I had our 54 Super, I had one valve that was stuck down causing zero compression. I knew it had a miss right off the bat when I drove it off the trailer. It turned out to be the valve guide that had worked its way down a bit. Pretty sure it had stuck inside the guide and took the guide with it when initially started. I pulled the head, removed the valve, tapped the guide back in place, reinstalled valve and reassembled the head. Problem solved. 1 Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 3 minutes ago, Smartin said: When I had our 54 Super, I had one valve that was stuck down causing zero compression. I knew it had a miss right off the bat when I drove it off the trailer. It turned out to be the valve guide that had worked its way down a bit. Pretty sure it had stuck inside the guide and took the guide with it when initially started. I pulled the head, removed the valve, tapped the guide back in place, reinstalled valve and reassembled the head. Problem solved. Inspiring! I sure hope that's all I need. But even if I need another valve....I've got a ton of used valves and a few boxes of new ones. Just all the extra work sucks. Link to post Share on other sites
Smartin 1,613 Posted February 4 Share Posted February 4 Yeah it's a pisser, but you can have the head off in an hour. You got this! 1 1 Link to post Share on other sites
Ben Bruce aka First Born 3,454 Posted February 4 Share Posted February 4 The joys of old cars. Ben Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 (edited) So in a few months it will be 24 years since I got my first classic car. Pretty sure I've run a lot on bad gas and never had a problem. Karma? Just the odds? Edited February 4 by NC-car-guy (see edit history) Link to post Share on other sites
avgwarhawk 4,012 Posted February 4 Share Posted February 4 2 minutes ago, NC-car-guy said: So in a few months it will be 24 years since I got my first classic car. Pretty sure I've run a lot on bad gas and never had a problem. Karma? Just the odds? Just a lot of sitting without being ran would be my guess. Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 Matt Martin commented on my facebook post that one cannot lap in a replacement and they must be ground and that I should replace all the valve guides and the exhaust valves since they tend to break. I think I'm going back to Ford products after this. I've run a worn out 300 inline six on duct tape and coat hangers for tens of thousands of miles... these GM engines are too needy! Link to post Share on other sites
old-tank 3,703 Posted February 4 Share Posted February 4 4 hours ago, JohnD1956 said: Before tearing it down have you considered pulling the valve up and charging the cylinder with pressurized air? Might just be a broken spring on that valve. If the seats were addressed when you had the heads off previously I don't think a seat could be ruined with what little use it has had since then.if the air holds that valve in position, changing that spring might be enough to get her back in the groove. Take the rocker assembly off and apply some penetrating oil at the valve stem/valve guide area. Tap with a small hammer and the valve may pop up, if it does follow up with some light oil; replace rockers and crank. Not uncommon for valves to stick on a long dormant low mileage engine; OR of the heads were at a machine shop they will see the valve to guide clearance too tight (chevy specs). Buick specs: valve stem clearance in guide: 0.0025 inlet 0.0030 exhaust If you replace one valve you need to set the valve stem height the same as the others or: 1.525 to 1.550 measured (in inches) from valve cover rail to valve stem tip. Link to post Share on other sites
avgwarhawk 4,012 Posted February 4 Share Posted February 4 3 minutes ago, old-tank said: Take the rocker assembly off and apply some penetrating oil at the valve stem/valve guide area. Tap with a small hammer and the valve may pop up, if it does follow up with some light oil; replace rockers and crank. Not uncommon for valves to stick on a long dormant low mileage engine; OR of the heads were at a machine shop they will see the valve to guide clearance too tight (chevy specs). Buick specs: valve stem clearance in guide: 0.0025 inlet 0.0030 exhaust If you replace one valve you need to set the valve stem height the same as the others or: 1.525 to 1.550 measured (in inches) from valve cover rail to valve stem tip. This is a sound plan of attack. Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 14 minutes ago, old-tank said: Take the rocker assembly off and apply some penetrating oil at the valve stem/valve guide area. Tap with a small hammer and the valve may pop up, if it does follow up with some light oil; replace rockers and crank. Not uncommon for valves to stick on a long dormant low mileage engine; OR of the heads were at a machine shop they will see the valve to guide clearance too tight (chevy specs). Buick specs: valve stem clearance in guide: 0.0025 inlet 0.0030 exhaust If you replace one valve you need to set the valve stem height the same as the others or: 1.525 to 1.550 measured (in inches) from valve cover rail to valve stem tip. How does one measure from the valve cover rail to the valve stem tip? Is this the gasket surface? Also how does one "set the height" without grinding metal off? Link to post Share on other sites
old-tank 3,703 Posted February 4 Share Posted February 4 1 minute ago, NC-car-guy said: How does one measure from the valve cover rail to the valve stem tip? Is this the gasket surface? Also how does one "set the height" without grinding metal off? Gotta grind. Yes, gasket surface. If you do this, put a straight edge over the valve stems and they should be pretty close to the same....just match that height. Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 1 minute ago, old-tank said: Gotta grind. Yes, gasket surface. If you do this, put a straight edge over the valve stems and they should be pretty close to the same....just match that height. I don't have the equipment or the know-how for grinding valves. Sounds like an expensive trip to the machine shop. Link to post Share on other sites
old-tank 3,703 Posted February 4 Share Posted February 4 2 minutes ago, NC-car-guy said: I don't have the equipment or the know-how for grinding valves. Sounds like an expensive trip to the machine shop. You should be able to find a machine shop that will do one valve, but do it yourself: lap the new valve with grinding compound and carefully grind the stem with your bench grinder to match the others. You worry too much.. 1 1 Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 (edited) 10 minutes ago, old-tank said: You should be able to find a machine shop that will do one valve, but do it yourself: lap the new valve with grinding compound and carefully grind the stem with your bench grinder to match the others. You worry too much.. Ha Ha Ha! Your are right about that! I do worry a lot. Some people I talk to would have me believe if I sneeze while the valve cover is off it will implode on next start up 😳😳 I've never rebuilt a buick engine. Ford 302s and international inline 6s I've built in my kitchen lol. Heck even my cadillac is a patchwork of junkyard parts in her 425 and I run that car in two modes, stop and full throttle ha ha ha. I don't worry about it and that's probably why its my favorite right now. Edited February 4 by NC-car-guy (see edit history) Link to post Share on other sites
avgwarhawk 4,012 Posted February 4 Share Posted February 4 The manual shows how to handle the lap, etc. With luck it is just a valve stuck in the guide and a minor repair. 1 Link to post Share on other sites
Bloo 1,533 Posted February 4 Share Posted February 4 7 hours ago, NC-car-guy said: Barring any damage to the head or piston, can I just lap in a new valve? Should I replace head gaskets again? Should I replace the head bolts? Yes, you can lap one valve in. You must definitely check the stem height and set it correctly because Buicks do not have selective length pushrods. The lifter preload and rocker arm geometry on a Buick depends on the valve stem height being at a predictable dimension, then no other adjustments are usually made. Also measure the valve spring installed height. It is much less likely to be a problem, but check it. Again? The heads were already off?! If you have to pull the head, use a new gasket. Get the same brand and type` the other side has. Bolts are not torque-to-yield, and are not normally replaced on these old engines unless there is some obvious problem. If you are worried about it, measure their length and look for stretched ones. I'll bet you don't find any. 7 hours ago, JohnD1956 said: Before tearing it down have you considered pulling the valve up and charging the cylinder with pressurized air? Might just be a broken spring on that valve. If the seats were addressed when you had the heads off previously I don't think a seat could be ruined with what little use it has had since then.if the air holds that valve in position, changing that spring might be enough to get her back in the groove. Good plan. 6 hours ago, NC-car-guy said: Seats were not previously addressed. At 13k miles that thought did not cross my mind. Unfortunately I cant pull up on the valve, hence stuck. Matt Martin told me that as little as 1 liter of bad fuel in an entire tank can gum up the valve stem and cause it to bend like this one. 4 hours ago, NC-car-guy said: So in a few months it will be 24 years since I got my first classic car. Pretty sure I've run a lot on bad gas and never had a problem. Karma? Just the odds? Ugh. So have I, always getting rid of most of it first, but never worried to much about a little residue back in the day. Then one day some bad gas stuck a bunch of valves in an an old Mercury (390 Ford) I inherited from my dad. The gas wasn't even that old, maybe a couple of years. No more than four. It bent a bunch of pushrods, and ran so badly It would not drive. I pulled the valvesprings to change the seals using the cylinder full off rope method. The stuck valves were stuck so badly I couldn't believe it. Lots of penetrating oil and brake cleaner, and still I had to whale on them repeatedly with a brass hammer to get them unstuck, and then repeatedly wash out the guides with more brake cleaner and penetrating oil. These were not new tight guides. The engine has over 200k miles. Once clean, they were about as loose as you would expect them to be, not horrible but definitely loose compared to new. Modern gas rots fast. I think this is probably the new normal. The nailhead valves are at such an angle compared to the pistons, I can't help but wonder if yours is bent. If it isn't bent, you can probably fix it from the top if you want. 2 Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 1 hour ago, Bloo said: Yes, you can lap one valve in. You must definitely check the stem height and set it correctly because Buicks do not have selective length pushrods. The lifter preload and rocker arm geometry on a Buick depends on the valve stem height being at a predictable dimension, then no other adjustments are usually made. Also measure the valve spring installed height. It is much less likely to be a problem, but check it. Again? The heads were already off?! If you have to pull the head, use a new gasket. Get the same brand and type` the other side has. Bolts are not torque-to-yield, and are not normally replaced on these old engines unless there is some obvious problem. If you are worried about it, measure their length and look for stretched ones. I'll bet you don't find any. Good plan. Ugh. So have I, always getting rid of most of it first, but never worried to much about a little residue back in the day. Then one day some bad gas stuck a bunch of valves in an an old Mercury (390 Ford) I inherited from my dad. The gas wasn't even that old, maybe a couple of years. No more than four. It bent a bunch of pushrods, and ran so badly It would not drive. I pulled the valvesprings to change the seals using the cylinder full off rope method. The stuck valves were stuck so badly I couldn't believe it. Lots of penetrating oil and brake cleaner, and still I had to whale on them repeatedly with a brass hammer to get them unstuck, and then repeatedly wash out the guides with more brake cleaner and penetrating oil. These were not new tight guides. The engine has over 200k miles. Once clean, they were about as loose as you would expect them to be, not horrible but definitely loose compared to new. Modern gas rots fast. I think this is probably the new normal. The nailhead valves are at such an angle compared to the pistons, I can't help but wonder if yours is bent. If it isn't bent, you can probably fix it from the top if you want. Thanks for the info. I also appreciate the story...misery loves company! Link to post Share on other sites
NC-car-guy 3,129 Posted February 4 Author Share Posted February 4 2 hours ago, Bloo said: Again? The heads were already off?! If you have to pull the head, use a new gasket. Get the same brand and type` the other side has. Eventhough they are brand new? Link to post Share on other sites
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